JAK2 exon 12 mutations in cases with JAK2V617F-negative polycythemia vera and primary myelofibrosis.

Molecular detection of JAK2 mutation (V617F or exon 12) is included as a major diagnostic criterion for polycythemia vera (PV) by the WHO 2016 guidelines. JAK2 exon 12 mutations are seen in about 2-5% of JAK2V617F-negative cases of PV. Mutations in JAK2 cause constitutive activation of JAK-STAT pathway which results in variable phenotypes. PV patients with exon 12 mutations in JAK2 present characteristically with erythrocytosis. There are limited reports describing the spectrum of JAK2 exon12 mutations in myeloproliferative neoplasms (MPNs). Here, we describe the characteristics of a series of MPN patients with mutations in exon 12 of JAK2 of which two were novel variants associated with polycythemia. Interestingly, we noted two patients presenting as myelofibrosis having JAK2 exon 12 mutations.

Screening of genetic variants in ELANE mutation negative congenital neutropenia by next generation sequencing.

AIMS: Congenital neutropenia (CN) is a rare inherited disease that results in recurrent, life-threatening bacterial infections due to a deficiency of mature neutrophils. They are usually caused by heterozygous ELANE mutations although mutations in other genes like HAX-1, G6PC3 and GFI1 have also been reported. Identifying the causative mutation aids in the establishment of diagnosis and rules out other secondary causes of neutropenia like autoimmune cytopenia and evolving aplasia. We aimed to identify the molecular defects in CN patients who had no mutations in ELANE gene, by next generation sequencing (NGS) targeting a customised panel of genes. METHODS: DNA samples were sequenced with an Illumina NextSeq sequencer using an in-house customised panel of genes at ≥100× depth. Bioinformatics analysis was carried out and the pathogenic variants were identified using a stepwise filtering and analysis strategy. Specific mutations identified were subsequently validated by Sanger sequencing. RESULTS: The pathogenic variants identified in the study includes previously reported variants in SBDS (compound heterozygous c.258+2T>C and c.1A>T), GATA2 (heterozygous c.1186C>T) and novel variants in WAS (hemizygous c.812T>C), JAGN1 (homozygous c.70G>A) and RTEL1 (heterozygous c.2893G>C) genes. CONCLUSION: This study highlights that the absence of ELANE mutations does not rule out the diagnosis of CN and this NGS based approach with a customised panel will help in diagnostic confirmation in such patients. The early onset of the disease, clinical severity and associated high risk of malignant transformation in CN strongly suggests the need for early diagnosis and therapeutic intervention.